1. Field of the Invention
The present invention relates to a dosage dispenser for such products as toliet tank additives, e.g. disinfectants, detergents, and the like. More particularly, the present invention relates to a dispenser which comprises no moving parts and employs air locks to isolate the additive-containing solution to be dispensed from the water in the toilet tank during quiescent periods between flushes.
1. Description of the Prior Art
Devices for dispensing a disinfectant solution into a toilet tank for flow into the toilet bowl when the tank is flushed are known. It is generally desired to isolate the disinfectant from the water in the toilet tank during quiescent periods between flushes. To this end, it is known to use valves or other mechanisms which will shut off flow from the dispenser when the toilet tank is filled to a desired level. See, for example, U.S. Pat. Nos. 1,307,535; 2,692,165; 3,073,488; 3,341,074; 3,698,021; 3,778,849; 3,784,058; 3,895,739; and 4,036,407.
Passive dispensers which are devices having no moving parts are also known. In one type of such passive dispensers, the dispensers are alternately flooded and the siphoned when the tank is flushed. See, for example, U.S. Pat. Nos. 650,161; 1,144,525; 1,175,032; 1,213,978; and 3,339,801. In another type, the dispensers are alternately flooded and then drained gravitationally. See, for example U.S. Pat. Nos. 1,987,689; 3,121,236; 3,504,384; 3,545,014; 3,618,143; 3,604,020; 3,772,715; 3,781,926; 3,943,582; and 4,244,062. In addition, U.S. Pat. Nos. 2,688,754; 3,864,763; and 3,965,497 and U.K. Pat. No. 705,904 disclose toilet chemical dispensers in which a small amount of the chemical is released into the tank in the absence of hydrostatic pressure on the spout thereof, e.g., when the toilet has been flushed and the water level in the tank has dropped. As the tank becomes filled with water, the resulting hydrostatic head prevents the solution from being released from the dispenser. In a further type of passive dispenser, the solution to be dispensed is connected to a pressurized water supply such as the trap refill pipe in a toilet tank. See, for example U.S. Pat. Nos. 3,407,412 and 3,444,566 wherein the direction of flow alternates in labyrinth passages. In all of the abovementioned passive dispensers, due to the construction thereof, the disinfectant can flow or diffuse into the toilet tank water.
Passive dispensers using air locks, i.e. pockets of air, to isolate the disinfectant from the tank water during quiescent periods in a toilet tank have been disclosed. For example, U.S. Pat. Nos. 4,171,546 and 4,216,027 disclose passive dispensers which issue a predetermined volume of a toilet tank additive solution into a toilet tank as the water is draining therefrom when the toilet is flushed. According to these patents, an amount of a concentrated additive solution is drawn from a storage place into the tank as the water level therein drops resulting from flushing. The devices are provided with numerous baffles and passageways to form air locks that isolate the concentrated disinfectant solution from the tank water when the toilet tank is in a quiescent state. In these devices, the air locks are located at the top of the device. U.S. Pat. No. 4,186,856 discloses a passive dispenser having air locks formed in the top portion thereof when submerged to isolate the tank water from the disinfectant stored therein. Another passive dispenser is disclosed in U.S. Pat. No. 4,208,747 wherein air locks are also employed to isolate the disinfectant from tank water during quiescent periods. However, the air locks in this dispenser are disposed at different levels whereas those employed in the dispensers of the '546, '856 and '027 patents are at the same level and in the top portion thereof. U.S. Pat. No. 4,251,012 discloses another passive dispenser in which a disinfectant is issued into a toilet tank in measured quantities. Although air locks are also used to isolate the disinfectant from the tank water, this device is so constructed that the disinfectant is stored in a compartment which is not accessible to the tank water, even when the device is completely submerged. The air locks provided in this device are located at the same level near the top portion thereof.
The above mentioned passive dispensers have a common disadvantage, namely, their construction is complex. Tortuous flow paths are required in these devices. As a result, they are difficult to manufacture. Another disadvantage is that for the devices to function properly, these devices must be hung substantially vertically in the tank. Tilting of these devices away from the wall means that the devices will extend into the center portion of the tank and interfere with the operation of the mechanisms, such as outlet valve and float linkage, in the tank. This is particularly significant in the device shown in U.S. Pat. No. 4,208,747 which is equipped with a siphon tube. The presence of the siphon tube means that the lower end of the device is substantially below the water surface. A slight tilt away from the tank wall at the top of the tank will cause the siphon tube, because of its length, to extend into the center of the tank and substantially away from the wall. Thus, there is a need for a passive dispenser which has a simple construction and does not have a length which will cause problems resulting from tilting.